Add `force_no_page` LDAP configuration

Zendesk: https://gitlab.zendesk.com/agent/tickets/65090

Currently, LDAP configuration does not allow passing the force_no_page option to Net::LDAP. In this case, Net::LDAP defaults to false and tries to detect whether the server supports paging or not. In this customer's case, the detection isn't working, and things started to work once we hacked the library to force no paging. It appears we'll need to add this for both GitLab LDAP and Omniauth LDAP - but Omniauth currently doesn't support this either. We should add the change it both places.

Since we haven't seen this before, and probably can't repro it, we should keep this customer in mind and use them as a test case.